Avaliação de agregados reciclados de resíduos da construção civil da cidade de Uberaba: uma perspectiva para a sua utilização em guias de meio fio

Abstract

The advancement of human population growth has brought with it the need for constant interventions and modifications in natural landscapes (e.g., city expansion). However, the adverse effects of this expansion have been primarily attributed to the waste generated throughout construction and demolition processes, causing impacts along the entire production chain. The use of Construction and Demolition Waste (CDW) as raw material to produce new products is increasingly common and presents numerous benefits, not only for the environment but also for consumers. The present study explores the viability and use of recycled aggregate from construction and demolition waste for the production of new products, specifically for curbstones. Initially, the recycled aggregates from CDW were characterized using sand and gravel samples from the Uberaba-MG region as a reference. Following NBR 15116, the coarse recycled aggregate was visually analyzed, separating particles according to their composition. Pulverulent content, specific mass, unit mass, and void volume were determined for comparison with natural sand and conventional gravel. After this, the concrete dosage was defined based on strength and workability requirements, considering tests. Finally, the concrete dosage was adjusted according to the specific needs for the manufacturing of curbstones and test specimens. The results obtained indicate that the recycled aggregates from CDW have a density similar to that of natural aggregates, with a considerable percentage of ceramic waste. Moreover, the specific mass of recycled aggregates from CDW (gravel and sand) was lower by 24.5% and 7.5%, respectively, when compared to conventional gravel and natural sands. The water absorption rate of the recycled aggregates from CDW was higher than that of natural aggregates. The test results show that the reference concrete exceeds the analyzed requirements, but the influence of recycled CDW aggregates in the dosage considerably reduces the strength parameters. However, for the manufacture of curbstones, it is feasible to use 50% and 100% CDW, even though it does not meet BT-82/ABCP standards, as it satisfies the strength requirements of DNIT 020/2006 – ES. This study suggests that the use of recycled aggregates has its challenges, but it is noticeable that there is excellent cost-benefit. Mainly employed in the replacement of non-structural concretes, recycled aggregate concrete presents greater environmental benefits compared to conventional concrete.